The present invention relates to a rotary laser device. The invention also relates to a method for controlling a laser beam.
Laser instruments that generate point-shaped and/or line-shaped laser markings are known for performing leveling or marking work in interior and exterior construction. The laser markings are used to indicate reference points or reference lines on walls, ceilings and floors. A distinction is made in terms of these laser instruments between point and/or line laser instruments and rotary laser devices. Point and/or line laser instruments generate point and/or line-shaped laser markings on a target surface by beam-forming optics such as cylindrical lenses and prisms and the markings are arranged at fixed angles to one another.
Known rotary laser devices comprise a laser device, which generates a laser beam, a rotating device, which moves the laser device at least partially around an axis of rotation at a rotation speed, and a measuring device, with which an angle of rotation of the laser device around the axis of rotation can be determined. Rotary laser devices are operated in a rotation mode, a scan mode and/or a point mode. In rotation mode, the laser beam is moved at a constant rotation speed around the axis of rotation and generates a continuous laser marking on a target surface. In scan mode, the laser beam moves back and forth between a first and second end point in a limited angle range and generates a line-shaped laser marking, designated as a laser line, on a target surface. In point mode, the rotation speed of the rotating device is zero and the laser beam generates a point-shaped laser marking, designated as a laser point, on a target surface.
In scan mode of a rotary laser device, there is a deceleration and acceleration of the laser device in the region of the end points of the delineated laser line and the laser beam rests at the end points. If the laser beam meets the human eye at the end points, the portion of the laser beam that is absorbed by the eye is greater than with a rotating laser beam and the risk of injury increases. In addition, the laser line is fuzzy in the region of the end points. The fuzziness of the laser line arises from the deceleration and subsequent acceleration of the laser device. Another disadvantage of known rotary laser devices is that in point mode only one single laser point is generated and known rotary laser devices are not suitable for transmitting angles of, for example, 90° or 180° from one target surface to another target surface.
Improving a rotary laser device with regard to the disadvantages explained above would be desirable. The object of the present invention is reducing the risk of injury to the operator when creating delineated laser lines with a rotary laser device. In addition, the rotary laser device is suitable for transmitting angles from one target surface to another target surface.
According to the invention, in the case of the rotary laser device, a memory device is provided for saving at least one angular position. Saving at least one angular position offers the possibility of controlling the laser beam as a function of the angle of rotation.
A control device is preferably provided which adjusts at least one beam property of the laser beam as a function of the angle of rotation. Suitable as beam properties of the laser beam are above all the laser power and, in the case of a modulated laser beam, the optical frequency and/or the amplitude. These beam properties are especially suited to generate sharply delineated laser lines and/or laser points on a target surface.
In a preferred embodiment, the memory device is configured as a mechanical memory device and arranged in the form of at least one reference element on a master disk of the measuring device. The measuring device includes a master disk, which is connected to the rotating device for rotation therewith, a scanning device for scanning the master disk and an evaluation and control device. In this case, the master disk is connected in a fixed manner to a rotatable shaft or is connected via gearwheels or toothed belts for rotation therewith. The advantage of a firmly connected master disk is that measurement of the angle of rotation is stable with respect to outside influences, above all temperature. Interconnecting a transmission ratio allows the resolution of the angle of rotation to be increased. The advantage of a mechanical memory device is that an additional component is not required for the memory device and detecting the angular position is stable with respect to outside influences.
It is especially preferred that the reference elements are arranged in the form of reference tracks on the master disk. The reference tracks are monitored by the scanning device of the measuring device.
In an alternative preferred embodiment, the memory device is configured as an electronic memory device, wherein the memory device is connected especially preferably to an input device. The advantage of an electronic memory device over a mechanical memory device is that the laser lines are generated with an arbitrary aperture angle and any angles may be transmitted from one target surface to another target surface. In addition, an electronic memory device allows saved angular positions to be deleted and new angular positions to be saved.
A laser receiver is preferably provided, wherein the laser receiver can be connected to the rotary laser device via a communication link. Because of the combination of the rotary laser device with a laser receiver, there is an opportunity to transmit information via the laser beam to the rotary laser device.
According to the invention, in the method for controlling a laser beam at least one angular position is saved in a memory device and at least one beam property of the laser beam is adjusted as a function of the angle of rotation. Because of the possibility of controlling the laser beam, it is possible to display delineated laser lines or laser points optically by changing beam properties of the laser beam.
The laser power of the laser beam and/or, in the case of a modulated laser beam, the optical frequency and/or the amplitude are adjusted as a function of the angle of rotation. These beam properties are especially suited for generating sharply delineated laser lines and/or laser points on a target surface.
In a first preferred method variant, a first and second angular position are saved in the memory device and at least one beam property of the laser beam is changed from a first value to a second value when the first angular position is reached and is changed from the second value to the first value when the second angular position is reached. This method variant is used to generate a delineated laser line on a target surface. To this end, the laser power as a beam property is switched between zero and a constant power value. Switching the laser power between zero and the constant power value takes place very rapidly so that a precisely delineated laser line is generated between the first and second end points, which correspond to the first and second angular positions. Because the laser beam is moved at constant rotation speed, the risk of injury to the human eye is reduced as compared to a resting laser beam.
In a second preferred method variant, a first and a second angle of rotation are calculated from the at least one saved angular position, and at least one beam property of the laser beam is changed from a first value to a second value when the first angle of rotation is reached and is changed from the second value to the first value when the second angle of rotation is reached. This method variant is used to generate one or more laser points on a target surface. To this end, the laser power as a beam property is switched between zero and a constant power value. The angular position of the laser point is saved in the memory device. The evaluation and control device of the measuring device determines a first angle of rotation from the angular position, which angle of rotation is smaller than the angular position, and a second angle of rotation, which is larger than the angular position. The distance between the first and second angle of rotation is selected in such a way that the laser power of the beam source may be switched and the laser point is easily visible to the operator. Because the laser beam is moved at a constant rotation speed, the risk of injury to the human eye is reduced as compared to a resting laser beam.
The invention also relates to a method for measuring an angle with a rotary laser device according to the invention, which has an electronic memory device and is connected to a laser receiver via a communication link. The momentary angle of rotation of the laser device or of the laser beam is saved in the memory device as the angular position when the laser beam strikes a detector device of a laser receiver. In order to increase the precision of the measurement, the detector device should be designed to be as small as possible or the detector device has a special detector field.
The laser receiver is positioned at a first point and the angular position is saved as the first angular position in the memory device and the laser receiver is subsequently positioned at a second point and the angular position is saved in the memory device as the second angular position. The angle between the first and the second point is determined as the difference between the angular positions saved in the memory device. This method offers the possibility of using a rotary laser device to measure angles.
Exemplary embodiments of the invention are described in the following on the basis of the drawings. These drawings are not necessarily supposed to represent the exemplary embodiments to scale; rather, the drawings are executed in a schematic or slightly distorted form when it is useful for explanatory purposes. Reference is made to the pertinent prior art with respect to additions to the teachings directly identifiable from the drawings. It must be taken into consideration in this case that a wide range of modifications and changes related to the form and detail of an embodiment can be undertaken without deviating from the general idea of the invention. The features of the invention disclosed in the description, the drawings as well as in the claims, may be essential for the further development of the invention both individually as well as in any combination. Moreover, all combinations of at least two features disclosed in the description, the drawings and/or the claims fall within the scope of the invention. The general idea of the invention is not restricted to the exact form or detail of the preferred embodiment described and depicted in the following or restricted to a subject matter, which would be limited as compared to the subject matter claimed in the claims. In the case of any dimensioning ranges given, values within the stated limits are also meant to be disclosed as limit values, and be applicable at will and claimable. For the sake of simplicity, the same reference numbers are used in the following for identical or similar parts having an identical or similar function.